U.S. patent number 5,151,884 [Application Number 07/844,148] was granted by the patent office on 1992-09-29 for control system for appliance indicator light and method for using same.
This patent grant is currently assigned to Maytag Corporation. Invention is credited to Scott E. Griffith, Charles L. Jackson, Barry E. Tuller.
United States Patent |
5,151,884 |
Griffith , et al. |
September 29, 1992 |
Control system for appliance indicator light and method for using
same
Abstract
A control system for an appliance indicator light includes a
timer which times the amount of time the appliance door is open
after completion of the operational cycle of the appliance. If the
door is opened for more than a predetermined period of time, the
indicator light will be deactuated, but if the door is opened for
less than the predetermined period of time and then reclosed, the
indicator light will be left in its on condition. The timer may be
a series of cams attached to a motor, a bi-metal switch located
adjacent the indicator light, or a microprocessor connected to and
driving the indicator light.
Inventors: |
Griffith; Scott E. (Newton,
IA), Tuller; Barry E. (Newton, IA), Jackson; Charles
L. (Newton, IA) |
Assignee: |
Maytag Corporation (Newton,
IA)
|
Family
ID: |
25291946 |
Appl.
No.: |
07/844,148 |
Filed: |
March 2, 1992 |
Current U.S.
Class: |
368/10;
134/57D |
Current CPC
Class: |
A47L
15/0049 (20130101); A47L 15/46 (20130101); A47L
15/4259 (20130101); A47L 15/4293 (20130101); A47L
2401/20 (20130101); A47L 2501/26 (20130101) |
Current International
Class: |
A47L
15/42 (20060101); G04B 047/00 (); G06F
015/46 () |
Field of
Search: |
;368/9,10
;134/57R,57D,58R,58D |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Whirlpool Corporation, "New Generation Dishwashers Compactors"
Copyright 1991. .
Sears, Roebuck and Co. "Kenmore Dishwashers" 1991. .
General Electric Company "Built-In Dishwashers" Aug. 28, 1991.
.
Caloric Corporation "Caloric Built-In and Portable Dishwashers"
Aug. 28, 1991..
|
Primary Examiner: Miska; Vit W.
Attorney, Agent or Firm: Zarley, McKee, Thomte, Voorhees,
& Sease
Claims
We claim:
1. A control system for controlling an indicator light for an
appliance after said appliance has completed an operational cycle,
said appliance having an access door being in a closed position
during said operational cycle and movable to an open position, said
control system comprising:
an electrical power source;
door switch means connected to said power source and being movable
to a first posture in response to said door being moved to said
open position and being movable to a second posture in response to
said door being moved to said closed position;
timing means connected to said door switch and being operable
responsive to said door switch moving to said first posture after
completion of said operational cycle for causing initiation of a
timing cycle which continues for a predetermined period of
time;
controller means connected to said timing means and said power
source for connecting said power source to said indicator light
until said timing means completes said timing cycle, and for
disconnecting said indicator light from said power source when said
timing means completes said timing cycle.
2. A control system according to claim 1 wherein said timing means
comprises a bi-metal strip switch.
3. A control system according to claim 2 wherein said bi-metal
strip switch is positioned adjacent said indicator light and is
responsive to heat emanating from said indicator light to move from
an open position to a closed position and is responsive to the
absence of heat emanating from said indicator light to return to
said open position.
4. A control system according to claim 3 wherein said bi-metal
strip switch completes a circuit from said power source to said
indicator light when in said closed position and creates an open
circuit between said power source and said indicator light when in
said open position.
5. A control system according to claim 4 wherein said controller
means comprises a controller switch connected between said power
source and said indicator light and after completion of said
operational cycle being adapted to move from a closed position
connecting said power source to said indicator light to an open
position disconnecting said power source from said indicator light
through said controller switch.
6. A control system according to claim 5 wherein said controller
means further comprises actuator means for selectively moving said
controller switch between its said open and closed positions.
7. A control system according to claim 1 wherein said timing means
comprises a timer motor.
8. A control system according to claim 7 wherein said controller
means comprises a first switch between said timer motor and said
power source and being movable from a closed position actuating
said timer motor and an open position deactuating said timer
motor.
9. A control system according to claim 8 wherein said controller
means further comprises a second switch between said indicator
light and said power source, said second switch being movable from
a closed position connecting said indicator light to said power
source to an open position disconnecting said indicator light from
said power source.
10. A control system according to claim 9 wherein said timing means
further comprises cam means drivingly connected to said timer motor
and engageable with said first and second switches for moving in
response to actuation of said timer motor to cause said first and
second switches to move between their said open and closed
positions according to a predetermined pattern throughout said
timing cycle.
11. A control system according to claim 10 wherein said controller
means still further comprises a third switch between said timer
motor and said power source and being movable from a closed
position for actuating said timer motor to an open position
preventing actuation of said timer motor through said third
switch.
12. A control system according to claim 11 wherein said cam means
is engageable with said third switch means for causing said third
switch means to move from said closed to said open position when
said first and second switches are moved by said cam means to their
said closed positions respectively.
13. A control system according to claim 1 comprising a
microprocessor connected between said door switch means and said
indicator light, and being programmed with a computer program, said
timing means comprising a timing portion of said program and said
controller means comprising a controller portion of said
program.
14. A control system for controlling an indicator light for an
appliance after said appliance has completed an operational cycle,
said appliance having an access door being in a closed position
during said operational cycle and movable to an open position, said
control system comprising:
door switch means movable to a first posture when said door is in
said open position and being movable to a second posture when said
door is in said closed position;
computer means connected to said door switch and said indicator
light, said computer means being programmed with a computer program
which causes said computer means to actuate said indicator light
upon completion of said operational cycle of said appliance and to
remain in said actuated condition for a predetermined period of
time after said door is moved to said open position, said computer
program causing said computer means to turn said indicator light to
a deactuated condition after said door has been in said open
position for said predetermined period of time.
15. A control system for controlling an indicator light for an
appliance, said appliance having an access door movable between an
open position and a closed position, said control system
comprising:
an electrical power source;
door switch means connected to said power source and being movable
to a first posture in response to said door being moved to said
open position and being movable to a second posture in response to
said door being moved to said closed position;
timing means connected to said door switch and operable in a first
predetermined timing cycle with said access door in said closed
position, said timing means further operable in a second
predetermined timing cycle following completion of said first
predetermined timing cycle responsive to said door switch moving to
said first posture;
controller means connected to said timing means and said power
source for connecting said power source to said indicator light
during said second predetermined timing cycle, and for
disconnecting said indicator light from said power source on
completion of said second predetermined timing cycle.
16. A control system according to claim 15 wherein said first
predetermined timing cycle comprises an operational cycle for said
appliance.
17. A method for controlling an indicator light for an appliance
after said appliance has completed an operational cycle, said
appliance having an access door being in a closed position during
said operational cycle and being movable from said closed position
to an open position, said method comprising:
enabling an electrical circuit containing said indicator light
after completion of said operational cycle of said appliance
whereby said indicator light will be in an actuated condition;
sensing when said door is moved to said closed position and when
said door is moved to said open position;
starting timer means in response to said door being moved to said
open position, said timer means being adapted to move through a
timing cycle in a predetermined time interval;
preventing said timer means from reaching completion of said timing
cycle whenever said door is moved to said closed position before
said timer means completes said timing cycle;
disabling said electrical circuit containing said indicator light
whenever said timer means completes said timing cycle whereby said
indicator light will be in a deactuated condition.
Description
BACKGROUND OF THE INVENTION
This invention relates to a control system for an appliance
indicator light and a method for using same. The invention is
particularly useful in dishwasher appliances.
Various devices have been used in dishwashers to indicate when the
washing cycle is complete and to indicate when the dishes within
the dishwasher are clean. One device used for this purpose in the
prior art is a clean indicator light which comes on when the
dishwashing cycle is complete, and which indicates to the user that
the dishes are clean. In most prior art dishwashers, these clean
indicator lights are turned off as soon as the operator opens the
dishwasher door and will remain off if the door is reclosed.
However, the users of dishwashers often open the dishwasher to
remove a single object without removing all of the clean dishes
within the dishwasher. In prior art devices, the opening of the
door causes the clean indicator light to go off and remain off,
even though the door is sometimes closed with many clean dishes
remaining in the dishwasher. There is therefore a need for a clean
indicator light which will remain on when the operator opens the
door for a short period of time to remove a single item and then
recloses the door, without removing all of the clean dishes within
the dishwasher.
SUMMARY OF THE INVENTION
Therefore a primary object of the present invention is the
provision of an improved control system for an appliance clean
indicator light and an improved method for using same.
A further object of the present invention is the provision of a
control system which causes the clean indicator light to remain on
when the dishwasher door is closed after being open for a short
period of time to remove a single object, but which causes the
clean indicator light to be deactuated after the dishwasher door
has been open for a long period of time to remove all of the clean
dishes from within the dishwasher.
A further object of the present invention is the provision of a
system for controlling the appliance clean indicator light which is
completely automatic.
A further object of the present invention is the provision of an
improved control system for an appliance clean indicator light
which is economical to manufacture, durable in use, and efficient
in operation.
The present invention utilizes a timer which commences operation
during the time that the door is open, and which disables the clean
indicator light only after the passage of a predetermined amount of
time.
The control system for the clean indicator light generally includes
a door switch connected to the access door of the appliance. The
switch is movable to a first posture in response to the access door
being opened and is movable to a second posture in response to the
access door being closed. A timer connected to the door switch
operates in a first predetermined timing cycle with the access door
in its closed position. The timer operates in a second
predetermined timing cycle following completion of the first
predetermined timing cycle in response to the door switch moving to
its first posture. A controller is connected to the timer and a
power source for connecting the power source to the clean indicator
light during the second predetermined timing cycle and for
disconnecting the clean indicator light from the power source on
completion of the second predetermined timing cycle.
Three different embodiments of the invention are shown. The first
embodiment of the invention utilizes an electric timer motor as a
timing device. On the completion of the washing cycle, the timer
motor causes a pair of contacts to be closed. The first of these
contacts completes a circuit to the clean indicator light, and the
second of the contacts completes a circuit to the timer motor. The
timer motor is then shut off, and the clean indicator light remains
on so long as the dishwasher door is closed. When the dishwasher
door is opened, a switch within the dishwasher door completes the
electrical circuit to the timer motor, thereby actuating the timer
motor. A series of cams are connected to the timer motor, and one
of these cams engages and controls a switch between the power
source and the clean indicator light. If the door is kept open for
a sufficiently long period of time, for example 100 seconds, the
cams rotate to a position to cause the circuit to be broken between
the power source and the clean indicator light, thereby disabling
the clean indicator light. However, if the door is open only for a
short time, the closing of the door causes the timer motor to be
deactuated before the circuit is broken between the clean indicator
light and the power source. Only after the door has been left open
for the full 100 seconds do the cams from the timer motor cause the
circuit to be broken between the clean indicator light and the
power source.
In a second modified form of the invention, the clean indicator
light is initially turned on by a circuit actuated by the timer
motor. A bi-metal strip switch is then utilized as a timer in place
of the timer motor. The bi-metal strip switch is positioned closely
adjacent to the clean indicator light, and the heat from the clean
indicator light causes the bi-metal strip switch to move to a
closed circuit position completing the circuit between the power
source and the clean indicator light whenever the door is in its
closed position. When the door is moved to its opened position, the
circuit is broken to the clean indicator light, but the bi-metal
strip switch remains in its closed position for a short period of
time. If the dishwasher door is left open a sufficiently long
period of time, the bi-metal strip switch will cool and move to its
open position, and the closing of the dishwasher door will not
reactuate the clean indicator light. However, if the dishwasher
door is kept open for a short period of time, the bi-metal strip
switch will remain in its closed position, and the closing of the
dishwasher door will again complete the circuit to the clean
indicator light through the bi-metal strip switch, and cause the
clean indicator light to be reactuated.
A third modified form of the present invention utilizes a
microprocessor to control the clean indicator light which in this
form is a LED. The microprocessor senses when the dishwasher door
is open or closed. At the end of the dishwashing cycle, if the
dishwasher door is closed, the microprocessor causes the clean
indicator light to be actuated. The opening of the dishwasher door
triggers a switch which signals to the microprocessor that the door
is open, thereby starting a timer within the microprocessor. If the
timer is permitted to expire, it disables the clean indicator light
so that the clean indicator light will not go on after closing of
the dishwasher door. However, if the dishwasher door is left open
only for a short period of time and then closed again, the timer
within the microprocessor is set back to its beginning value, and
the clean indicator light is not disabled.
BRIEF DESCRIPTION OF FIGURES OF THE DRAWINGS
FIG. 1 is a perspective view of a dishwasher installed beneath a
kitchen cabinet.
FIG. 2 is a schematic view of one modified form of the present
invention utilizing a series of cams to operate the various
switches in the circuit.
FIG. 3 is a view similar to FIG. 2, showing the cams in a different
position.
FIG. 4 is a view similar to FIG. 3, but showing the door switch in
a different position.
FIG. 5 is a view similar to FIGS. 2-4, but showing the door switch
in a closed position and the other switches in an open
position.
FIG. 6 is a schematic view of a second modified form of the present
invention utilizing a bi-metal strip switch as a control
switch.
FIG. 7 is a view similar to FIG. 6, but showing the door switch in
an open position.
FIG. 8 is a view similar to FIG. 7, but showing both the door
switch and the bi-metal strip switch in an open position.
FIG. 9 is a schematic view of a third modified form of the present
invention utilizing a microprocessor as a controller for the clean
indicator LED.
FIG. 10 is a flow chart showing the method of operation of the
circuitry in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a conventional dishwasher having a front door 8
and having a clean indicator light 22 on the control panel. In the
embodiments shown in FIGS. 1-8, the clean indicator light 22 is
preferably an incandescent bulb. In the embodiment of FIGS. 9 and
10, the clean indicator light 22 is preferably a LED. The clean
indicator light 22 is adapted to be on after the dishwasher has
completed its washing and drying cycle. The purpose of clean
indicator light 22 is to indicate that the dishes are clean and
ready for removal. The present invention contemplates means for
timing the amount of time that the door 8 is open for removal of
dishes so that if the door 8 is open for only a short time, the
clean indicator light will be on when the door is reclosed.
However, if the door 8 is open for a substantial length of time,
the timing mechanism of the present invention causes the clean
indicator light to be deactuated until after the next cycle so that
it will not come on again after the door 8 is closed.
FIGS. 2-5 illustrate a control system 10 for accomplishing the
above result. System 10 includes an electrical input line 12 which
is connected to a door switch 14 which is connected to door 8, and
which is responsive to the opening and closing of the door 8.
Switch 14 may be a mercury switch or a mechanical switch and is
adapted to move to its upper most position shown in FIGS. 2, 3, and
5 when the door 8 is closed and to its lower most position shown in
FIG. 4 when the door 8 is open. System 10 includes a motor switch
16 and a light switch 18 which are shown in their open positions in
FIGS. 2 and 5, and which are shown in their closed positions in
FIGS. 3 and 4. Switches 16, 18 are controlled by a timer motor 20
which is connected to a cam shaft 26 having a first cam 28, a
second cam 30, and a third cam 32 thereon. System 10 also includes
clean indicator light 22 and a master washing cycle switch 24. The
numeral 34 indicates the neutral or ground wire of the circuit.
During the washing and drying cycle of the dishwasher, the third
cam 32 is in the position shown in FIG. 2 holding master switch 24
in its closed position. This causes motor 20 to be actuated so that
the cam shaft 26 rotates continuously during the washing and drying
cycle. Also during the washing and drying cycle, the first and
second cams 28, 30 are in the position shown in FIG. 2 causing
motor switch 16 and light switch 18 to be in their open
positions.
Upon completion of the washing and drying cycle of the dishwasher,
cam 32 has rotated to the position shown in FIG. 3, leaving master
switch 24 in its open position and causing motor 20 to be
deactuated. At this time, the first and second cams 28, 30 have
been moved to the position shown in FIGS. 3 and 4 so as to cause
motor switch 16 and light switch 18 to be closed. The closing of
light switch 18 causes clean indicator light 22 to come on thereby
indicating to the user of the dishwasher that the washing and
drying cycle is complete and the dishes are clean. Throughout the
washing and drying cycle, the door 8 is in its closed position as
shown in both FIGS. 2 and 3.
When the operator of the dishwasher desires to remove one or more
of the clean dishes from the dishwasher, that person opens the door
8 thereby causing door switch 14 to move from its upper position
shown in FIG. 3 to its lower position shown in FIG. 4. Because
motor switch 16 is held in its closed position by cam 28, the
opening of the door introduces electrical power to the motor 20
thereby actuating motor 20. The actuation of motor 20 causes shaft
26 to begin rotating. The shape of cams 28, 30 is such that the
operation of the motor 20 for a period of 100 seconds causes the
cams 28, 30, 32 to move from the position shown in FIG. 4 to the
position shown in FIG. 5. This results in the opening of switches
16, 18, thereby deactuating the motor 20. As further shown in FIG.
4, when the door 8 is open and the motor 20 is operating, power to
the clean indicator light 22 will be interrupted.
However, if the door 8 is left open only for a few seconds, as
opposed to 100 seconds and then is closed, the motor 20 is shut off
before it completes its cycle from the position shown in FIG. 4 to
the position shown in FIG. 5. Since the cycle is not complete, the
switches 16, 18 remain in their closed position as shown in FIG. 4.
This causes the clean indicator light 22 to come on again when door
8 is moved to its closed position to cause door switch 14 to move
to its upper position. While the preferred time for the cycle of
the clean indicator light 22 is 100 seconds, different cycles can
be selected merely by changing the shape of cams 28, 30.
Thus, the system 10 shown in FIGS. 2-5 causes the clean indicator
light 22 to return to the on condition if the door 8 is open for a
short period of time and is then closed, but causes the clean
indicator light 22 to be deactuated if the door 8 is left open for
a long period of time. Thus it is possible to remove one or two
dishes from the dishwasher, close the door 8, and still have the
clean indicator light 22 in an on condition. Only if the door 8 is
open for a considerable length of time as would be the case in
removal of all the dishes, would the clean indicator light 22 be
deactuated.
Referring to FIGS. 6-8, a modified system 36 for controlling the
clean indicator light 22 is shown. System 36 includes a timer motor
38 which operates a cam 40 in a rotation direction indicated by the
arrow on cam 40. Timer motor 38 and cam 40 are timed with the
washing and drying cycle of the dishwasher so that cam 40 will move
to the position shown in FIG. 6 after the completion of the washing
and drying cycle. In the position shown in FIG. 6, cam 40 causes a
start switch 42 to be moved to its closed position. A door switch
44 is connected to door 8 and is adapted to be in its closed
position when door 8 is also closed. Thus, at the completion of the
washing and drying cycle, with switches 42, 44 in their closed
positions, electrical power is introduced from an input line 46 to
a clean indicator light 22 and ultimately to the ground wire 52.
This actuates the clean indicator light 22 which is positioned in
close proximity to a bi-metal strip switch 50. Bi-metal strip
switch 50 is adapted to be in its open position as shown in FIG. 8
normally, but when bi-metal strip switch 50 is exposed to heat such
as the heat emanating from clean indicator light 22, it responds by
moving to its closed position shown in FIG. 6. It should also be
noted that the motor 38 moves cam 40 to the position of FIG. 6
immediately upon the completion of the washing and drying cycle,
but that the motor 38 continues moving cam 40 to the position shown
in FIGS. 7 and 8, thereby opening switch 42 shortly after the
completion of the washing and drying cycle.
The opening of door 8 to remove one or more dishes, causes switch
44 to move to its open position as shown in FIG. 7. Immediately
upon the opening of the door, the clean indicator light 22 is
deactuated, but the bi-metal strip switch 50, because of the
residual heat which it retains, does not immediately move to its
open position. Bi-metal strip switch 50 will only move to its open
position after a sufficient amount of time has passed to permit it
to cool so that it will move to its open position. Thus, if the
dishwasher door 8 is left open only for a short time, the bi-metal
strip switch 50 will remain in its closed position, and if the door
8 is closed again after a short period of time, the system resumes
its condition as shown in FIG. 6, thereby causing the clean
indicator light 22 to return to the on condition.
However, if the dishwasher door 8 is left open for a substantial
period of time, the bi-metal strip switch 50 moves to its open
position, and the reclosing of the door 8 does not cause the clean
indicator light 22 to come on. This condition is shown in FIG.
8.
FIGS. 9 and 10 illustrate a further modified form of the invention
designated by the numeral 54. System 54 utilizes a microprocessor
56 manufactured by National Semiconductor under the designation
COP840C. The microprocessor 56 is programmed with a program causing
it to control all of the various cycles of the dishwasher. The
program within microprocessor 56 is also adapted to control the
operation of a clean indicator light 22 comprising a LED. System 54
includes a power input line 58 which is connected to a door switch
60 shown in its closed position in FIG. 9, which is the position
switch 60 takes when the door 8 is in its closed position. Switch
60 moves to its open position in response to opening of door 8, and
the open position of switch 60 is shown in dashed lines in FIG. 9.
A door sensor 62 is an opto isolator, and a preferred embodiment of
this opto isolator is manufactured by Motorola Company under the
designation 4N27. Sensor 62 is connected to door switch 60 and is
adapted to sense when a potential of 120 volts is experienced
across the inlet line 68 and the outlet line 70 which are connected
to sensor 62. Thus, when the switch 60 is in its closed position,
the sensor 62 senses a voltage potential of 120 volts, and sends a
signal to the microprocessor 56 that the 120 volts has been sensed
and the door switch 60 is in its closed position. The program
within microprocessor 56 receives this signal and is adapted to
process the signal for controlling a LED driver 64 which drives
clean indicator light 22. The LED driver 64 is manufactured by
Sprague Company under the designation ULN 2003.
FIG. 10 illustrates the process by which the computer program in
microprocessor 56 operates. The program controls the washing cycle
and the drying cycle, and includes a counter which counts down to
zero when the washing and drying cycles are complete. This step in
the process is indicated by the box 72 in FIG. 10. The
microprocessor 56 then senses whether or not the timing counter is
down to zero as indicated by the diamond shape box 74. If the
program determines that the counter has reached zero, it turns off
all of the LEDs on the control panel of the dishwasher except for
the LED comprising the clean indicator light 22. The computer
program then checks to determine whether or not the clean LED is in
fact still on, and this step is indicated by the diamond shape box
78. If the clean LED is on, the program then checks to see if door
8 is open, and this is accomplished by responding to the signal
from door sensor 62. If door sensor 62 indicates that the door 8 is
closed, the computer program loads a timing counter for 30 seconds
as indicated in box 82. The program then immediately checks to see
if the counter is at zero, and because the counter was loaded
immediately preceding this, diamond shape box 84 will indicate that
the counter is not at zero and will return to the top of the cycle
above box 74. The program will then go through the steps outlined
in boxes 74, 78, 80 and 82 so long as the door switch 60 is in its
closed position. Each time the program reaches the step shown in
box 82, it reloads the counter for another 30 seconds, and because
it takes less than 30 seconds for the cycle to be complete, the
counter never registers zero so long as the door 8 remains in its
closed position.
When the operator opens the door 8 for a short period of time, the
program bypasses the step of box 82, and continues through box 84
back to box 74 so long as the door 8 is open. If the door 8 is open
for less than 30 seconds, and then is closed, the program goes from
box 80 to box 82, thereby reloading the counter and preventing the
clean LED of clean indicator light 22 from going off. However, if
the door 8 is open for more than 30 seconds, the counter reaches
zero, and when the program reaches box 84, it senses a zero in that
counter and turns off the clean LED of clean indicator light
22.
Thus, the system shown in FIGS. 9 and 10 causes the clean LED of
the clean indicator light 22 to remain on so long as the door 8 is
kept open less than 30 seconds, but if the door 8 is open for 30
seconds or more, then the clean LED of clean indicator light 22 is
turned off. The present invention insures that the clean indicator
light 22 will remain on if the operator opens the door 8 for a
short period of time to remove a few dishes and then recloses the
door 8. However, if the operator opens the door 8 for sufficient
length of time to remove all of the dishes, then the clean
indicator light 22 is deactuated and remains off. The device is
simple and economical to manufacture, and is efficient in its
operation.
The preferred embodiment of the invention has been set forth in the
drawings and specification, and although specific terms are
employed, these are used in a generic or descriptive sense only and
are not used for purposes of limitation. Changes in the form and
proportion of parts as well as in the substitution of equivalents
are contemplated as circumstances may suggest or render expedient
without departing from the spirit or scope of the invention as
further defined in the following claims.
* * * * *